Business Acquisitions - Proforma information (Details) - Titan - USD ($) $ in Thousands	3 Months Ended
Jul. 31, 2018	Jul. 31, 2017
Pro forma information
Pro forma net sales	$ 820,813	$ 767,834
Pro forma operating income	$ 8,367	$ 17,236

Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Balance Type:	credit
Period Type:	duration